title: Gyroscopic destabilisation in polyatomic molecules: rotational structure of the low-frequency bending vibrational states ν(23) and ν(11) of dimethylsulfoxide.
abstract: We give details of the spectroscopic observation of the gyroscopic destabilisation in the ν23 vibrational state of dimethylsulfoxide (DMSO) announced by Cuisset, Pirali, and Sadovskií [Phys. Rev. Lett. 109, 094101 (2012)]. Following the first successful high-resolution spectroscopic study of the rotational structure of the "perpendicular" band of DMSO at 324 cm(-1) associated with the ν23 bending vibrational mode, the rare subsystem of ν23 rotational levels consisting of a series of fourfold quasidegenerate levels (4-clusters) was identified. Our complete analysis of the underlying rotational dynamics uncovered a bifurcation leading to the gyroscopic destabilisation of one of the two stable principal axes of inertia, a phenomenon known previously only in a few triatomic molecules.
authors.affiliation: Laboratoire de Physico-Chimie de l'Atmosphère, Département de physique, Université du Littoral - Côte d'Opale, 59140 Dunkerque, France. Arnaud.Cuisset@univ-littoral.fr
authors.forename: Arnaud
authors.initials: A
authors.lastname: Cuisset
authors.forename: Dmitrií A
authors.initials: DA
authors.lastname: Sadovskií
mesh_terms: D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory; D014732:Vibration
chemical_list: D004121:Dimethyl Sulfoxide